This invention relates generally to a heat exchanger or more explicitly to a recuperator and more particularly to a method and an apparatus for construction of the cells making up the recuperator.
A recuperator is made from a plurality of cells. The cell is made from a plurality of components parts. Such components being a pair of folded sheets having a donor side and a recipient side. A pair of wing portions defining an inlet passage and an outlet passage. In many cells, guide vanes are positioned in the respective wing portions. And, a plurality of spacer bars are positioned between the pair of folded sheets. The components of the cell are welded together. An example of such a welded cell and recuperator is shown in U.S. Pat. No. 5,060,721 issued on Oct. 29, 1991 to Charles T. Darragh.
During the assembly of the cells and the recuperator, the interface of the components are welded. The effectiveness of the welding process used to form the cells is in many instances depend on the fitting relationship of the components, the resulting configuration of the interface of the components and the welding process itself. The results of these variables in some instances results in a leaking cell, leakage between the donor side and the recipient side. Thus, it is necessary to inspect or check the reliability of the welded cell against leaks prior to installing into the recuperator. Inspection or checking must be done in a reliable and cost effective manner.
The present invention is directed to overcome one or more of the problems as set forth above.
In one aspect of the invention, an apparatus for testing a leak within a cell of a recuperator is disclosed. The cell has a plurality of components, such components being a plurality of primary surface sheets, a plurality of spacer bars and a pair of guide vanes. The apparatus has a table having a bottom portion and a top portion. The top portion is movable between a closed or testing position and an open or non testing position. A pair of sealing mechanisms is movable between an open or non testing position and a closed or testing position. A vacuum pump is operatively connected to the pair of sealing mechanisms and a controller is operatively connected to the table, the pair of sealing mechanisms and the vacuum pump.
In another aspect of the invention, a method of testing for a leak within a cell for a recuperator is disclosed. The cell has a plurality of components, such components being a plurality of primary surface sheets, a plurality of spacer bars and a pair of guide vanes. The method has the steps of positioning the cell on a bottom portion of a table with a top portion of the table being in an open or non testing position. Moving the top portion into a closed or testing position. Securing the top portion in the closed or testing position to the bottom portion of said table. Actuating a controller. Moving a pair of sealing mechanisms from an open or non testing position to a closed or testing position. Actuating a vacuum pump. Defining a status of the cell by differentiating between an operational cell and a failed cell. Unsecuring the top portion from the bottom portion of the table. Moving the top portion into the open or non testing position. And, removing the cell from the table.
In another aspect of the invention, a system for testing a cell for use in a primary surface recuperator is disclosed. The system has an input station from which the cell after being assembled is made available for testing. A testing station includes a table, a pair of sealing mechanisms, a controller, a vacuum pump and a readout station. The table has a top portion and a bottom portion. The top portion is movable between an open or non testing position and a closed or testing position. In the closed or testing position of the top portion the cell is positioned in the bottom portion and the top portion is positioned in the closed or testing position. The pair of sealing mechanisms is attached to the bottom portion of the table and is movable between an open or non testing position and a closed or testing position. In the closed or testing position of the pair of sealing mechanisms the cell has a first end of a passage in contacting sealing relationship with a one of the pair of sealing mechanisms and a second end of the passage in contacting sealing relationship with an other one of the pair of sealing mechanisms. The controller is in communication with a plurality of sensors. A portion of the plurality of sensor communicates a signal to the controller defining one of a position at which the closed or testing position is operational and a position at which the closed or testing position is not operational. The vacuum pump is actuated by the controller depending on a plurality of signals from a portion of said plurality of sensors. The readout station defines a status of the cell by differentiating between an operational cell and a failed cell. An output station has a pair of positions, one of the pair of positions is an operational cell position and failed cell position.